METROPOLITAN Longwall 27 Outburst Events Presenter Name Andy Hyslop General Manager Presenter Title Presenter Title
Metropolitan Lw 27 Outburst Events Agenda • Metropolitan Lw history • Location Plan • Geological overview • Gas Drainage overview • 200 series Outburst events • Summary of Lw 27 Outburst Events • Lw 27 Remote mining techniques • DMT peer review / study into German Lw outbursts • Changes to Outburst Control Plan
Metropolitan Lw History • Commenced Longwall mining operations 1995 • 26 Longwalls extracted since 1995 • Extraction Width 158m • #89 shields • Lw mined through numerous geological structures with no known or recorded Lw outburst events prior to Lw 27 • Joy Lw commissioned Lw 23 200 series • Average daily Lw tonnes 10,000 • Outburst Management Plan Prior to Lw 27 events “ The ORC will review the proposed longwall extraction area and issue a PTM for Longwall extraction or part there of”
Metropolitan Location Plan Lw 27 200 Series
Metropolitan Geological Overview • Bulli Seam • Seam height 2.7-3.4m • Variable topography • Depth of cover 400m to 540m • Major stress orientation 045-060 ° grid north, NE-SW • Geological structures: dyke zones, strike-slip faults, normal faults and thrust faults • Well developed persistent coal cleats
Metropolitan Geological Location Plan
Metropolitan Gas Drainage Overview • 200 Series average virgin seam gas content 15m ᶟ t at 90-100% Co2 • Drill Rigs • 1 x Lm90 • 2 x Lm75 • Borehole spacing's 20m or less • Yearly average drilling metres 60,000 – 80,000m • Average drainage time to allow below outburst threshold development 5-6 months • No Gas vacuum plant gas free vented into exhaust shaft
Metropolitan Gas Drainage Location Plan
Metropolitan 200 Series Outburst Events
Metropolitan Lw 27 Outburst Event #1 Lw 27 Outburst Event #1 Date: 23-12-2016 Time: 2:10 PM Description: No evidence of forced ejection of material with failed coal largely remaining within cavity AFC was operational. Low energy outburst event. • MG Chainage: 208m • TG Chainage: 210.2m • Cavity Location: 68# and 69# • F-0001 Fault location: 67/68# • Volume of material: Estimated to be 65 Tonnes • Volume of Gas released: 670m3 or 670,000 litres • Estimated gas content of outburst coal: 10.3m3/t (by calculation)
Metropolitan Lw 27 Outburst Event #1 11
Metropolitan Lw 27 Outburst Events - Gas Drainage 12
Metropolitan Lw 27 Outburst Event #1 • Prohibition notice issued to Metropolitan • Risk Assessment undertaken • SOP developed mainly focussing on position of operators • 20 shields on M/G side of shearer • Minimum manning on face • Operators to carry personal gas detectors • 10 scheduled days before recommencing Lw production – Xmas Shutdown • Prohibition notice removed
Metropolitan Lw 27 Outburst Event #2 Lw 27 Outburst Event #2 Date: 3-01-2017 Time: 3:42 PM Production: 5 shears from event #1 Description: No evidence of forced ejection, toppling failure, coal largely remaining within cavity • MG Chainage: 203.8m • TG Chainage: 205.8 • Cavity Location: 65# • F-0001 Fault location: 63# and 64# • Shearer TG drum position: 59/60# • Shearer MG drum position: mid 51# • Volume of material: Estimated to be 7-8 Tonnes (By calculation) • Volume of Gas released: 532m3 or 532,000 litres
Metropolitan Lw 27 Outburst Event #2
Metropolitan Lw 27 Outburst Event #2 • Production ceased • Area inspected by ORC • Regulator contacted and briefed • Operations resumed under SOP
Metropolitan Lw 27 Outburst Event #3 Lw 27 Outburst Event #3 Date: 4-01-2017 Time: 1:38 PM Production: 3 shears form event #2 Description: Major outburst event • MG Chainage: 201.5m • TG Chainage: 203.5m • Cavity Location: between 55# to 62# • F-0001 Fault location: 61# • Shearer TG drum position: 58# • Shearer MG drum position: 49# • Volume of material: Estimated to be 750 tonnes • Volume of Gas: Tailgate 6,382m3 or 6,382,000 litres (sensor max out 15 mins)
Metropolitan Lw 27 Outburst Event #3 M/G
Metropolitan Lw 27 Outburst Event #3 T/G
Metropolitan Lw 27 Outburst Event #3 Operator Position • Shearer operator and chock man XAM5600 off scale Co2 • Deputy XAM5600 <1.25% Co2
Metropolitan Lw 27 Outburst Events - Gas Data 23 December 2016 ~65 Tonnes ~ 670m 3 CO 2 Peak reading TG>5% for 3min 3 January 2017 ~8 Tonnes ~ 530m 3 CO 2 Peak reading TG 1.51% 4 January 2017 ~200 Tonnes ~ 11,100m 3 CO 2 Peak reading TG>5% for 15min 21
Metropolitan Lw 27 Outburst Event #3 - Gas Data • LW27 Outburst Event - 4th January 2017 starting at 1:38am • Total Duration above background 5.7hrs (343 minutes) • Background CO 2 0.9% (Pre & Post event) • Peak Reading CO 2 5% at 1:40am (15mins above sensor scale) • Additional volume of gas measured at TG - approx 6,600 m 3 CO 2
Metropolitan Lw 27 Outburst Events - Tonnages Each event moved approximately the following coal tonnages: ~750 Tonnes 750 ~8 Tonnes ~65 Tonnes 23
Metropolitan North West Mains Fault Grid Main West Fault Zone North Main West • Strike Slip Fault • ~ 4km strike length • Fault orientation ~ 062 ° GN • Seam displacement ~ 0.15m (vertical) LW27 • Outburst Mylonite thickness 100-350mm • Fault zone width 1.2m to 7m • Overburden thickness 420m • Major Horizontal Stress orientation 045-060 ° GN • Elevated stress (development) • Face Cleat 280 ° GN typically inclined 85 ° West
Metropolitan Lw 27 Outburst Events – Geology F- 0001 Slickensides at seam roof contact Mylonite
Metropolitan Lw 27 Outburst Event #3 • Prohibition notice issued to Metropolitan “no normal mining to occur on Lw 27 through outburst prone structure F - 0001” • Core sampling program undertaken either side of geotechnical structure F- 0001 • Lw Remote mining techniques reviewed • 50m no go zone from M/G end of outburst prone structure • 20min wait time after structure has been disturbed
Metropolitan Lw Remote mining from CME
Metropolitan LW Remote mining from face DCB
Metropolitan Lw Remote mining from Pump DCB
Metropolitan Lw 27 Remote Mining Control Measures Key Control Measures: • ORC to determine outburst mining control zone when LW is mining through outburst prone geological structures • PTM to be issued in increments of 10m of retreat distance per permit. • The Exclusion Zone and structure location is to be demarcated on the LW face using reflective markers • Whilst LW is producing through outburst control zone, maximum manning levels on return side of CME is to be 3 persons. • Once the shearer has passed to the tailgate side of the exclusion zone and any ‘double - chocking’ (if required) in the Exclusion Zone has been undertaken, a 20 minute wait time will commence. After this time has elapsed, normal production can continue on the Tailgate side of the Exclusion Zone
Metropolitan Lw 27 Remote Mining Control Measures Shearer Operations: • Cycle time to be increased by reducing shearer speed on MG cut run from 10m/min to 5m/min. Flit speed to be maintained as per normal operations. • As a minimum the exclusion zone will be set a minimum of 30 shields on the MG side and 15 shields on the TG side of the structure position (as determined by the ORC), relative to the projected structure position and retreat distance authorised in the PTM • Each PTM will specify the shearer remote operating position to meet the requirements of the Exclusion Zone • Shearer operator to carry gas monitor at all times whist on return side of CME • Should CO2 levels reach 3.0% or greater on the TG Face CO2 monitors, than shearer haulage is to be automatically stopped until gas levels decline under 3.0%.
Metropolitan Lw 27 Remote Mining Control Measures Shield Operations: • The PTM will specify the ‘Shield Operator’ off siding the shearer operator remote operating position to meet the requirements of the exclusion zone • Shield operator to carry gas monitor at all times whist on return side of CME • Shield advance to be operated on automation • Turn on Landmark to allow automated face alignment • If shield does not advance on automation, the shield is to be operated remotely using the new Roadway Remote Mimic If double chocking is required through faulted area – these shields are to be operated remotely using the new Roadway Remote Mimic. An additional 20 minute wait time is to apply prior to proceeding to continue normal production on the inbye side of any double chocked shields in the structure zone
Recommend
More recommend
